1. Technical Field
The present invention relates to a clock generation circuit, a detection device, a sensor, an electronic apparatus, and a moving object.
2. Related Art
In the past, there has been known a clock generation circuit using an oscillator circuit. In such an oscillator circuit, there is performed a temperature compensation for reducing the fluctuation of the oscillation frequency with respect to a temperature variation. As the related art of the temperature compensation of the oscillator circuit, there have been known technologies disclosed in JP-A-6-169237 (Document 1) and JP-A-2002-33644 (Document 2).
In the related art of Document 1, for example, the temperature compensation of the oscillation frequency is realized by supplying a ring oscillator circuit having a negative temperature characteristic with a bias current having a positive temperature characteristic.
In the related art of Document 2, the temperature compensation of the oscillation frequency is realized by constituting a resistance part of a CR oscillator circuit by two types of resistors different in temperature characteristic from each other.
However, in the related art described above, a reference voltage generation circuit, one or more operational amplifiers, and an amplifier circuit (a buffer circuit) become necessary, and there is a problem that the current consumption and the circuit size increase. Further, although in the related art of Document 2, a diffused resistor of P+ is used for the temperature compensation, since the sheet resistance value of the diffused resistor of P+ is low, the occupation area of the diffused resistor of P+ becomes large in order to ensure a necessary delay amount, and there is a problem that the layout area of the circuit device increases.
Further, a gyro sensor for detecting a physical quantity varied due to an external factor is incorporated in an electronic apparatus such as a digital camera or a smartphone, or a moving object such as a vehicle or a plane. The gyro sensor detects a physical quantity such as angular velocity, and is used for a so-called image stabilization, posture control, GPS autonomous navigation, and so on. As one of the gyro sensors, there has been known a crystal piezoelectric vibration type gyro sensor using a crystal oscillator.
In such a gyro sensor, the control section of the detection device is made to operate using a clock signal having the same frequency (e.g., 100 kHz) as the oscillation frequency (a drive frequency) of the crystal oscillator. For example, the control section is made operate using a sync signal for synchronous detection generated by a drive circuit of the detection device as a clock signal. Therefore, since the frequency of the clock signal becomes a frequency as low as, for example, 100 kHz, a high-speed operation of the control section cannot be realized. Further, since the stable clock signal cannot be obtained until the oscillation of the crystal oscillator is stabilized, the start-up time until the beginning of detection of a desired signal is delayed, and there is a problem that it takes long time before appropriate angular velocity data is output. Further, in the case of adopting a configuration of a digital gyro incorporating an A/D converter circuit and a digital signal processing section in the detection device, there is also a problem that the digital processing such as a digital filter process cannot be performed at high speed if the frequency of the clock signal is low.